The present invention relates spine visualization in 3D medical images, and more particularly to reformatting 3D medical images for improved visualization of the spine.
3D medical images, or volumetric medical data, such as computed tomography (CT) images, typically contain a wealth of anatomical information. For example, a chest CT image taken to evaluate a patient's airways may also contain valuable information concerning the patient's spine. In order to view the spine in such CT image, the volumetric data can be analyzed using standard two 2D slices. However, using standard 2D slices to analyze spine information in the volumetric data is a tedious task, and it can be hard to see curvature and abnormalities of the spine since the spine passes through slices at an angle. It is possible to use volume rendering to view the volumetric data in 3D, but it is difficult to obtain an unobstructed view of the spine using standard volume rendering techniques because other anatomic structures, such as the ribs, block the view of the spine.
An approach to simple evaluation of the spine was presented in Vrtovec, et. al., “Curved planar reformation of CT spine data,” SPIE Medical Imaging, pg. 1446-1456. 2005. In this process, a curved multiplanar image was obtained from the data via a spinal centerline. The centerline was computed by fitting a polynomial to a distance transform that is determined from a thresholded version of the image. The disadvantages of this method include the computational expense required from creating a distance function in the entire volume, a lack of robustness due to the specific choice of threshold, a high potential for overfitting due to the allowance of very high degree polynomials, and a lack of validation on the method itself with only one dataset tested. The method is not fully automatic and requires user input in order to complete, limiting its use for clinical applications. Finally, the method does not guarantee smooth transitions within the determined contour, limiting its utility in visualization.